Internal collet



Feb. 1, 1949. M. FULLER 2,460,414

I INTERNAL COLLET Filed July 20, 1946 Patented Feb. 1, 1949 Morell M. Fuller, San J acinto, Calif.

Application July 20, 1946, Serial No. 685,104

This invention relates to an internal collet, or work-holder, for use in connection with lathes, milling machines, etc., and refers particularly to a device which is intended to grip a workpiece from an interior bore thereon.

It is the general object of the present invention to provide an. improved form of internal col- 7 let or work-holder.

More particularly, it is an object of the present invention to provide a work-holder for use on lathes, etc., which work-holder is so constructed and arranged that it is adapted to hold a work piecerfrom the inner bore thereof to permit further machine work on the workpiece, which device is characterized by the fact that it holds the workpiece very accurately from its inner bore so that it is possible, if desired, to remove and rechuck the workpiece.

Another object of the present invention is to provide an internal collet or work-holder which is adapted to automatically adjust itself to grip the inside of a workpiece even when the interior bore'of the workpiece is not entirely round.

Another object of the present invention is to provide an internal collet which may be used in production operations on a clutch chuck, which internal collet is adapted for operation with a lathe running at full speed so that the work can 'be removed and replaced without interrupting the operation of the lathe.

A furtherobject of the present invention is to simplify and reduce the cost of constructing an internal collet Without interfering with the efiiciency and accuracy of the device in use.

Various other objects and advantages of the collet of the present invention will be apparent from the following description of a preferred example of the invention. The description is given in connection with the accompanying drawings, in which Figure 1 is a side view showing the device in use in an ordinary chuck.

Figure 2 is an end view.

Figure 3 is a section on the line 3-3 of Fig. 2, separated from the chuck and adapter.

Figure 4 is a side view in vertical section of the adapter.

Referring to the drawings, the device of the present invention includes three complementary jaw members 2 which may be assembled together to form a substantially cylindrically shaped body, the individual jaws making angles of 120 with each other. Each jaw member includes a work supporting side 3 and an operating side 4. The outer surfaces of the jaws on the side 3 unite 5 Claims. (Cl. 279-2) to form a nearly continuous cylindrical surface. Between the sides 3 and 4 there is provided a flange 5 having a groove in which is positioned a spring ring 6. The spring ring 8 serves only to prevent the three difierent jaw members from becoming separated, when the device is not in use.

Interiorly of the jaw members, at about the point of alignment with the flange 5, the jaw members collectively provide a substantially spherical socket in which is mounted a ball I. The ball 1' serves to act as a universal pivot or fulcrum for the jaw members in the manner hereinafter described. At the operating side i the members collectively provide an internal groove in which is mounted a ring 8 of resilient material, such as rubber, of sufficient size and resiliency to cause the pivoting of the jaw members around the ball I so that they contact together in the positions indicated in Figs. 2 and 3. The operating side 4 of the jaw members provides a somewhat smooth, substantially cylindrical, surface 9 for the purpose hereinafter described, and there is preferably supplied a slightly enlarged end Hi.

In using the device of the present invention. the right-hand side, or side 3, is inserted into the bore of the workpiece which is to be held. The operating side 4, or left-hand side, as seen in the drawing, is gripped by the holding element attached to the lathe or milling machine in which the device is to be used. As pressure is applied to the side 4, squeezing it together against the resilient rubber ring 8 by the member which holds the collet to the lathe or milling machine, then the side 3 of the device undergoes separation or expansion, applying pressure to the interior surfaces of the workpiece to be gripped by the device. In fact, any desired means may be applied for holding the collet of the present invention to the lathe or milling machine.

In Figs. 1 and 4, I have indicated the device positioned in an ordinary chuck, indicated at the dotted lines H, in Fig. 1. For fitting the device into an ordinary chuck it may be desirable to use an adapter such as indicated at I2 in Fig. 4. In Fig, 4 the adapter is a self-locking member having a flange l3 at its right end for limiting the movement of the adapter into the bore of the chuck H, and reduced as indicated at M to provide a shoulder i5. When the adapter is used with the collet of the present invention it will be seen that the shoulder it engages the shoulder of the enlargement [0. From the left end of the device are provided a plurality of slots l6 and from the right end of the device are provided a plurality of slots ll so that the device is capable of contracting under pressure.

While the particular form of the collet herein described is well adapted for carrying out the objects of the present invention, it will be understood that Various modifications and changes may be made, and this invention is not limited to the particular form shown, but includes all f such modifications and changes as come Within the scope of the appended claims.

I claim:

1. An internal collet for removably sustaining a workpiece from the inner bore thereof, which collet comprises jaw members uniting to form a substantially cylindrical body separated longitudinally into three separate jaw members, and a spherical fulcrum member positioned interiorly of the jaw members, the jaw members extending both sides of the fulcrum member so that at one side thereof they may expand and contract within the bore of the workpiece to be supported by thecollet and at the other side of the fulcrum they provide surfaces adapted to be contracted by a device for mounting the collet, said jaw members having segmental spherical surfaces engaging the fulcrum member.

2. An internal collet for removably sustaining a workpiece from the inner bore thereof, which collet comprises jaw members uniting to form a substantially cylindrical body separated longi- ,for yieldingly urging the jaw members into the releasing position.

3. An internal collet for holding a workpiece by the internal bore thereof, which collet comprises jaw members uniting to form a hollow cylindrical body, the body being divided longitudinally-to form three jaw members, the jaw members cooperating to form an internal spherical surface at its medial portion, and a ball engaging said surface for mounting the same as a fulcrum to permit one side of the jaw members to expand while the other side contracts.

4. Aninternal collet for holding a. workpiece by the internal bore thereof, which collet comprises jaw members uniting to form a hollow cylindrical body, the body being divided longitudinally'to form three jaw members, the jaw members cooperating to form an internal'spherical surface at its medial portion, a ball engaging the said surface for mounting the same as a fulcrum to permit one side of the jaw members to expand While the other side contracts, and a resilient ring yieldingly urging one side of the jaw members into expanded position.

5. An internal collet for holding a workpiece to the internal bore thereof, which collet comprises jaw members uniting to form a hollow cylindrical body, the body being divided longitudinally to form thre'ejaw members, the jaw members cooperating to form a spherical outer surface at each end, a ball engaging the jaw members for mounting the same on a fulcrum to permit one side of thejaw members to expand and contract while the other side contracts and expands, the jaw members having segmental spherical surfaces engaging said ball a resilient ring yieldingly urging one side of the jaw members into expanded position, and a retaining means for retaining the jaw members in assembled position.

MORELL M. FULLER.

REFERENCES CITED The following references are of record inthe file of this patent:

V V UNITED STATES PATENTS Number V 

